We turn now to trying to solve the most famous kidnapping since the lindbergh baby. In 1964 Paul Fronczak was snatched from a hospital by a woman posing as a nurse. Police pursued hundreds of leads until over a year later a little boy was found abandoned in a busy shopping area, 800 miles away in Newark, New Jersey. The fronczaks had their baby back, or did they? Almost 50 years later Paul took a DNA test to discover he really wasn't Paul Fronczak at all. So who was he and what happened to the real Paul snatched from his mother's arms a half century ago? ABC's chief investigative reporter Brian Ross with the next shocking part of the story. Reporter: Do you know who stole this baby? Yes. Who stole the baby? My mother. His name is Johnny Harbaugh and what he told us about his mother may seem far-fetched. But it most definitely is not. His mother's name was Linda Taylor, a notorious figure in Chicago in the 1970s and '80s. Dubbed America's welfare queen and vilified by president Ronald Reagan. The name is Linda Taylor. The alleged Illinois advisory committee on public assistance investigated, came up with 82 charges of welfare fraud, perjury and bigamy. Reporter: We began to look for her after our "20/20" tip line provided this clue, the baby was stolen by a lady known as the welfare queen. Linda Taylor died 12 years ago but we found her son living in a Chicago suburb, Harbaugh said he was a teenager living in this house in Chicago when he came home to discover a new baby. Was your mother capable of stealing a baby? My mother was capable of anything. Not only stealing a baby, but she could steal you. Reporter: Harbaugh said his mother was a master of disguise, could pass as white or black, porter rican or hawaiian. In her schemes to collect fraudulent welfare payments. Sometimes posing as a doctor or a nurse. She had a room with nothing but wigs and nurse dresses and shoes. Reporter: At the time that Paul Fronczak was stolen from the hospital, police put out a sketch. Yes. Reporter: Do you think that's your mother? Except for the nose but she could do anything with her face or her hair. Reporter: In the 1970s when Linda Taylor was put on trial for welfare fraud -- Miss Taylor, can we talk to you a moment? Reporter: She actually came under investigation for stealing the Fronczak baby. From one newspaper account, one of her ex-husbands told agents that miss Taylor appeared one day in the mid-1960s with a newborn baby although she had not been pregnant. So fascinating and Barbara Walters spent a lot of time covering the case, as well. Such a mystery. The story is not over. Tune in to "20/20" at 10:00, 9:00 central tonight for much more. Coming up on "Good morning

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